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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

EC10/NOEC: 500 mg/L for EDTA-Na2H2, corresponding to 411 mg/L HEDTA-H3.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
411 mg/L

Additional information

The toxicity of HEDTA on microorganisms is considered likely to be low based on read-across to the structural analogue, EDTA, and one available HEDTA study with a Klimish rating of 4. The key study for EDTA (Klimish rating 2, Van Ginkel & Stroo, 2000) tested the toxicity of Na2H2EDTA on microorganisms in an activated sludge. The EC10 value after 30 minutes was > 500 mg/L. Similar low toxicity was observed in additional studies on activated sludge. Nitrification inhibition tests were determent to be 700 mg/L (Hu et al 2003). Thus, inhibition of degradation activity of activated sludge is not anticipated when EDTA is introduced in appropriate low concentrations.